Blends of a polybutene-1 polymer, a polyolefin and a monoolefin copolymer rubber are known. U.S. Pat. No. 4,078,020 discloses such a composition containing (a) uncured ethylene-higher alpha olefin copolymer which optionally contains up to 5% of a diene, (b) crystalline isotactic polypropylene, and (c) crystalline isotactic butene-1 homopolymer. The composition of this reference is not crosslinked.
Also known are compositions of 1-butene polymer and a cured or partially cured thermoplastic elastomer. For example, U.S. Pat. No. 4,113,804 discloses compositions comprising a butene-1 polymer and thermoplastic elastomer comprising a substantially cured (80-90%) mixture of (1) an interpolymer of ethylene, polyene and at least one monoolefin having at least 3 carbon atoms, EPDM, (2) polyethylene, and (3) optionally, at least one polymer of a monoolefin having at least 3 carbon atoms, preferably polypropylene. In U.S. Pat. No. 4,247,652 is disclosed a thermoplastic elastomer blend comprising (A) a dynamically partially cured elastomer composition comprising (i) a peroxide-curable olefin copolymer rubber,(ii) a peroxide-decomposing olefin plastic, where the sum of (i) and (ii) is 100 parts, and (iii) a peroxide-non-curable hydrocarbon rubbery material and/or (iv) mineral oil and (B) an olefin plastic. In both of these patents the butene polymer is blended with a thermoplastic elastomer composition that has been cured or partially cured before the addition of the butene-1 polymer.
U.S. Pat. No. 4,650,830 discloses dynamically partially cured thermoplastic elastomer compositions comprising (A) an amorphous ethylene/alpha-olefin copolymer and (B) a polymer selected from the group consisting of (i) a low crystalline copolymer of propylene with alpha-olefin having at least 4 carbon atoms, (ii) a homopolymer or copolymer of 1-butene or (iii) the polymer of component (i) or component (ii) with a homopolymer or copolymer of an alpha-olefin having at least 3 carbon atoms. Preferably, the partial crosslinking is effected by grafting a radical polymerizable monomer having at least two polymerizable groups.